!(function(window, document) {
  var size = 4;//设置验证码长度
  function GVerify(options) { //创建一个图形验证码对象，接收options对象为参数
      this.options = { //默认options参数值
          id: "", //容器Id
          canvasId: "verifyCanvas", //canvas的ID
          width: "100", //默认canvas宽度
          height: "30", //默认canvas高度
          type: "number", //图形验证码默认类型blend:数字字母混合类型、number:纯数字、letter:纯字母
          code: "",
      }
      if(Object.prototype.toString.call(options) == "[object Object]"){//判断传入参数类型
          for(var i in options) { //根据传入的参数，修改默认参数值
              this.options[i] = options[i];
          }
      }else{
          this.options.id = options;
      }
      
      this.options.numArr = "0,1,2,3,4,5,6,7,8,9".split(",");
      this.options.letterArr = getAllLetter();

      this._init();
      this.refresh();
  }

  GVerify.prototype = {
      /**版本号**/
      version: '1.0.0',
      
      /**初始化方法**/
      _init: function() {
          var con = document.getElementById(this.options.id);
          var canvas = document.createElement("canvas");
          this.options.width = con.offsetWidth > 0 ? con.offsetWidth : "100";
          this.options.height = con.offsetHeight > 0 ? con.offsetHeight : "30";
          canvas.id = this.options.canvasId;
          canvas.width = this.options.width;
          canvas.height = this.options.height;
          canvas.style.cursor = "pointer";
          canvas.innerHTML = "您的浏览器版本不支持canvas";
          con.appendChild(canvas);
          var parent = this;
          canvas.onclick = function(){
              parent.refresh();
          }
      },
      
      /**生成验证码**/
      refresh: function() {
          this.options.code = "";
          var canvas = document.getElementById(this.options.canvasId);
          if(canvas.getContext) {
              var ctx = canvas.getContext('2d');
          }else{
              return;
          }
          
          ctx.textBaseline = "middle";

          ctx.fillStyle = randomColor(180, 240);
          ctx.fillRect(0, 0, this.options.width, this.options.height);

          if(this.options.type == "blend") { //判断验证码类型
              var txtArr = this.options.numArr.concat(this.options.letterArr);
          } else if(this.options.type == "number") {
              var txtArr = this.options.numArr;
          } else {
              var txtArr = this.options.letterArr;
          }

          for(var i = 1; i <=size; i++) {
              var txt = txtArr[randomNum(0, txtArr.length)];
              this.options.code += txt;
              ctx.font = randomNum(this.options.height, this.options.height) + 'px SimHei'; //随机生成字体大小
              ctx.fillStyle = randomColor(50, 160); //随机生成字体颜色        
              ctx.shadowOffsetX = randomNum(-3, 3);
              ctx.shadowOffsetY = randomNum(-3, 3);
              ctx.shadowBlur = randomNum(-3, 3);
              ctx.shadowColor = "rgba(0, 0, 0, 0.3)";
              var x = this.options.width / (size+1) * i;
              var y = this.options.height / 2;
              var deg = randomNum(-30, 30);
              /**设置旋转角度和坐标原点**/
              ctx.translate(x, y);
              ctx.rotate(deg * Math.PI / 180);
              ctx.fillText(txt, 0, 0);
              /**恢复旋转角度和坐标原点**/
              ctx.rotate(-deg * Math.PI / 180);
              ctx.translate(-x, -y);
          }
          /**绘制干扰线**/
        //   for(var i = 0; i < 4; i++) {
        //       ctx.strokeStyle = randomColor(40, 180);
        //       ctx.beginPath();
        //       ctx.moveTo(randomNum(0, this.options.width), randomNum(0, this.options.height));
        //       ctx.lineTo(randomNum(0, this.options.width), randomNum(0, this.options.height));
        //       ctx.stroke();
        //   }
          /**绘制干扰点**/
          for(var i = 0; i < this.options.width/4; i++) {
              ctx.fillStyle = randomColor(0, 255);
              ctx.beginPath();
              ctx.arc(randomNum(0, this.options.width), randomNum(0, this.options.height), 1, 0, 2 * Math.PI);
              ctx.fill();
          }
      },
      
      /**验证验证码**/
      validate: function(code){
          var code = code.toLowerCase();
          var v_code = this.options.code.toLowerCase();
          if(code == v_code){
              return true;
          }else{
              this.refresh();
              return false;
          }
      }
  }
  /**生成字母数组**/
  function getAllLetter() {
      var letterStr = "a,b,c,d,e,f,g,h,i,j,k,l,m,n,o,p,q,r,s,t,u,v,w,x,y,z,A,B,C,D,E,F,G,H,I,J,K,L,M,N,O,P,Q,R,S,T,U,V,W,X,Y,Z";
      return letterStr.split(",");
  }
  /**生成一个随机数**/
  function randomNum(min, max) {
      return Math.floor(Math.random() * (max - min) + min);
  }
  /**生成一个随机色**/
  function randomColor(min, max) {
      var r = randomNum(min, max);
      var g = randomNum(min, max);
      var b = randomNum(min, max);
      return "rgb(" + r + "," + g + "," + b + ")";
  }
  window.GVerify = GVerify;
})(window, document);